diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 85c00025a2ff..eac20112709c 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -646,7 +646,7 @@ intel_engine_has_relative_mmio(const struct intel_engine_cs * const engine)
 
 #define for_each_instdone_gslice_dss_xehp(dev_priv_, sseu_, iter_, gslice_, dss_) \
 	for ((iter_) = 0, (gslice_) = 0, (dss_) = 0; \
-	     (iter_) < GEN_MAX_SUBSLICES; \
+	     (iter_) < GEN_SS_MASK_SIZE; \
 	     (iter_)++, (gslice_) = (iter_) / GEN_DSS_PER_GSLICE, \
 	     (dss_) = (iter_) % GEN_DSS_PER_GSLICE) \
 		for_each_if(intel_sseu_has_subslice((sseu_), 0, (iter_)))
diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.h b/drivers/gpu/drm/i915/gt/intel_sseu.h
index 8a79cd8eaab4..b763b4e3dae6 100644
--- a/drivers/gpu/drm/i915/gt/intel_sseu.h
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.h
@@ -15,26 +15,49 @@ struct drm_i915_private;
 struct intel_gt;
 struct drm_printer;
 
-#define GEN_MAX_SLICES		(3) /* SKL upper bound */
-#define GEN_MAX_SUBSLICES	(32) /* XEHPSDV upper bound */
-#define GEN_SSEU_STRIDE(max_entries) DIV_ROUND_UP(max_entries, BITS_PER_BYTE)
-#define GEN_MAX_SUBSLICE_STRIDE GEN_SSEU_STRIDE(GEN_MAX_SUBSLICES)
-#define GEN_MAX_EUS		(16) /* TGL upper bound */
-#define GEN_MAX_EU_STRIDE GEN_SSEU_STRIDE(GEN_MAX_EUS)
+/*
+ * Maximum number of slices on older platforms.  Slices no longer exist
+ * starting on Xe_HP ("gslices," "cslices," etc. are a different concept and
+ * are not expressed through fusing).
+ */
+#define GEN_MAX_HSW_SLICES		3
+
+/*
+ * Maximum number of subslices that can exist within a HSW-style slice.  This
+ * is only relevant to pre-Xe_HP platforms (Xe_HP and beyond use the
+ * GEN_MAX_DSS value below).
+ */
+#define GEN_MAX_SS_PER_HSW_SLICE	6
+
+/* Maximum number of DSS on newer platforms (Xe_HP and beyond). */
+#define GEN_MAX_DSS			32
+
+/* Maximum number of EUs that can exist within a subslice or DSS. */
+#define GEN_MAX_EUS_PER_SS		16
+
+#define SSEU_MAX(a, b)			((a) > (b) ? (a) : (b))
+
+/* The maximum number of bits needed to express each subslice/DSS independently */
+#define GEN_SS_MASK_SIZE		SSEU_MAX(GEN_MAX_DSS, \
+						 GEN_MAX_HSW_SLICES * GEN_MAX_SS_PER_HSW_SLICE)
+
+#define GEN_SSEU_STRIDE(max_entries)	DIV_ROUND_UP(max_entries, BITS_PER_BYTE)
+#define GEN_MAX_SUBSLICE_STRIDE		GEN_SSEU_STRIDE(GEN_SS_MASK_SIZE)
+#define GEN_MAX_EU_STRIDE		GEN_SSEU_STRIDE(GEN_MAX_EUS_PER_SS)
 
 #define GEN_DSS_PER_GSLICE	4
 #define GEN_DSS_PER_CSLICE	8
 #define GEN_DSS_PER_MSLICE	8
 
-#define GEN_MAX_GSLICES		(GEN_MAX_SUBSLICES / GEN_DSS_PER_GSLICE)
-#define GEN_MAX_CSLICES		(GEN_MAX_SUBSLICES / GEN_DSS_PER_CSLICE)
+#define GEN_MAX_GSLICES		(GEN_MAX_DSS / GEN_DSS_PER_GSLICE)
+#define GEN_MAX_CSLICES		(GEN_MAX_DSS / GEN_DSS_PER_CSLICE)
 
 struct sseu_dev_info {
 	u8 slice_mask;
-	u8 subslice_mask[GEN_MAX_SLICES * GEN_MAX_SUBSLICE_STRIDE];
-	u8 geometry_subslice_mask[GEN_MAX_SLICES * GEN_MAX_SUBSLICE_STRIDE];
-	u8 compute_subslice_mask[GEN_MAX_SLICES * GEN_MAX_SUBSLICE_STRIDE];
-	u8 eu_mask[GEN_MAX_SLICES * GEN_MAX_SUBSLICES * GEN_MAX_EU_STRIDE];
+	u8 subslice_mask[GEN_SS_MASK_SIZE];
+	u8 geometry_subslice_mask[GEN_SS_MASK_SIZE];
+	u8 compute_subslice_mask[GEN_SS_MASK_SIZE];
+	u8 eu_mask[GEN_SS_MASK_SIZE * GEN_MAX_EU_STRIDE];
 	u16 eu_total;
 	u8 eu_per_subslice;
 	u8 min_eu_in_pool;